This sends NACK for missed packets and PLI (picture loss indication)
if a depacketizer indicates that it needs a new keyframe, according
to RFC 4585.

This is only enabled if the SDP indicated that feedback is supported
(via the AVPF or SAVPF profile names).

The feedback packets are throttled to a certain maximum interval
(currently 250 ms) to make sure the feedback packets don't eat up
too much bandwidth (which might be counterproductive). The RFC
specifies a more elaborate feedback packet scheduling.

The feedback packets are currently sent independently from normal
RTCP RR packets, which is not totally spec compliant, but works
fine in the environments I've tested it in. (RFC 5506 allows this,
but requires a SDP attribute for enabling it.)
Signed-off-by: Martin Storsjö <martin@martin.st>

This allows calling other dynamic payload handler functions if
needed.
Signed-off-by: Martin Storsjö <martin@martin.st>

The warning is a false positive, but I prefer actually initializing
it over masking it with av_uninit, since the code is not performance
critical.
Signed-off-by: Martin Storsjö <martin@martin.st>

This is a bug from c7d4de3d - if the previous frame wasn't
returned yet (due to missing the final packets), but we have
enough data of it to return the first partition, we write that into
pkt and set returned_old_frame. That commit forgot returning 0 for
the case where this current packet didn't have the end_packet flag
set.
Signed-off-by: Martin Storsjö <martin@martin.st>

Signed-off-by: Martin Storsjö <martin@martin.st>

Signed-off-by: Martin Storsjö <martin@martin.st>

Signed-off-by: Martin Storsjö <martin@martin.st>

If we timed out and consumed a packet from the reordering queue,
but didn't return a packet to the caller, recheck the queue status.
Otherwise, we could end up in an infinite loop, trying to consume
a queued packet that has already been consumed.

CC: libav-stable@libav.org
Signed-off-by: Martin Storsjö <martin@martin.st>

If the matrix results in an output channel not getting a contribution
from any input channel and the corresponding input channel does not
contribute to any outputs, we can skip the channel during mixing and
silence it after mixing.

If the matrix results in an input channel not contributing to any output
channels and it is not in the output mix, or if the input channel only
contributes fully to the same output channel, we can skip the channel
during mixing.

If the matrix results in an output channel only getting full
contribution from the corresponding input channel and that input channel
does not contribute to any other output channels, we can skip the
channel during mixing.

This allows reordering, duplication, and silencing of input channels.

Simplifies header dependencies by not including all other internal headers
in internal.h.

If a bug exists on the tracker, its ID should always be included
in fix messages.

Also, any relevant bug fixes should be CC'd to libav-stable, so
we can actually track what needs to be backported, instead of
just randomly combing the git history and old CVEs.
Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

It's obviously undesireable to blindly allocate memory based on
a damaged 'size' value, for example.
Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

It's pretty much the best tool for the job, and it's what we
all use now anyway.
Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

We obviously prefer git-send-email(1), and the disjointed nature
of the two statements was misleading.
Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

Signed-off-by: Diego Biurrun <diego@biurrun.de>

Plug an annoying memory leak on broken files.

Snow is a toy codec with no real-world use and horrible code.

255 to 174 cycles on Arrandale / Win64. Unrolling yields no gain.
Signed-off-by: Diego Biurrun <diego@biurrun.de>

698 to 174 cycles on Arrandale. Unrolling is a 6 cycles gain.
Signed-off-by: Diego Biurrun <diego@biurrun.de>